A quest I share with much of humanity, I believe, is the existential search to understand why I'm on this planet. Finally, I've narrowed the scope. More often now the question is: Why am I in this room?

Is it to find something? Am I walking through to another room?

There are myriad variations on this theme: Where are my glasses? Did I send a thank-you card to a friend? And if I seem to remember swallowing my vitamin, why is it still on the counter?

Am I getting more forgetful? Or have I always been forgetful?

Who can remember?

With approximately 10,000 Americans turning 50 every day, I'm guessing that I'm not alone in asking the question.

That's confirmed by Rose Marie Hall, manager of DeGraff Hospital's McLaughlin Center, which focuses on the wellness of older adults. Loss of memory is an oft-expressed fear, she says.

"A lot of times people are frightened because of the dread words 'Alzheimer's' and 'dementia,' " she said. "But I remind them that those are actual illnesses."

So what is this temporary blank-out that makes me wait for half an hour to remember the name of an acquaintance or a movie that I saw last week?

I've just learned: It's "benign senescent forgetfulness."

"It's not incremental," comes the reassurance of Marguerite Kermis, director of Canisius College's pre-med program and a specialist in aging. "We just lose some short-term memory and become a little less focused. We have so many memories hooked to so many things that sometimes it's tough to get the newer ones in."

At age 51, she knows this from textbooks and from life.

"I remember my mother calling us by the wrong names, and now I call my youngest daughter by the dog's name," she admits.

Leading busy lives and being distracted are valid reasons for not retaining all the bits of information that drift our way.

"The people I see are very active retirees who are still adding lots of new information," said Ms. Hall. "Their lives are definitely not leisurely."

We invent ways of coping: lists, calendar notes, Post-Its and my favorite -- calling home from work to leave a reminder on my answering machine.

But that doesn't help when I blank on someone's name, a common failing, experts say, because the brain is configured to forget as well as to remember.

The name problem is complicated because when people don't pay attention, they may miss the name the first time it's said. "Especially older people don't want to be rude and ask again," Ms. Hall said. "Or they might have a hearing problem and not want to admit it."

According to the authors of "The Forever Mind," new information is retained in sensory memory for one to three seconds before going to working memory, where it stays for a few seconds to two hours. Then, if it seems important to us and is reinforced several times, it becomes part of long-term memory.

If only we could pick and choose what we remember and what we forget. I wouldn't mind forgetting that Eddie Fisher's hit song was "Oh, My Papa" if I could only use that slot in my memory bank for remembering where I've parked my car at the Walden Galleria.

In these information-saturated times, we need to focus on what's essential and filter out what's not. But we've become so adept at filtering that sometimes we miss what's important. Then it's not that we forgot it, it's that we never got it, the authors say.

Ms. Hall suggests mind games to keep the brain clicking: "When you are standing in line at the supermarket, mentally rearrange your living room or try to add up your bill. Your mind needs exercise as much as your body does."

One theory is that keeping the body fit also reinforces mental acuity, perhaps because of increased blood flow to the brain.

"Also when you aren't feeling well, there may be some depression, and that always suppresses memory because it slows everything down," said Ms. Kermis.

I liked Ms. Hall's reassuring analogy that our minds are like computers, brimming with information.

"Sometimes you can get at it," she said. "Sometimes it runs at 286, sometimes 486 and sometimes at Pentium. The moment we go back to 286 we panic. We don't have to -- it may just take a little longer to retrieve the information."

Now, if only we could upgrade our memories as easily as we do those machines.